Nimbus is a noun that refers to a luminous cloud surrounding something.

The Latin word nimbus (NEEM boose) means ‘rainstorm,’ and, from this origin, our word of the day came to refer to a cloud or halo surrounding something or someone. Although often used in reference to supernatural beings, it can also be used more literally to simply refer to a large, gray rain cloud. Example:

The nimbus on the road up ahead suggests suggests our softball game is going to be cancelled today. That would be third game this year called off due to a pesky rain storm.